Method of and apparatus for producing compound metal objects.



B. E. EL'DRED. METHOD OF AND APPARATUS FOR PRODUCING comrouma MET AL OBJECTS. APPLICATION FILED JANHI, 190s. RENEWED my 9, 191

Patented Nov. 5, 1912.

Inventor: 6 M 6'. 514.4 Qu-e..e. %l

UNITED STATES PATENT orrioa BYRON E. ELDRED, or BRONXVILLE, NEW YORK, nssronon TO THE commncmn- RESEARCH COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

METHOD OF AND APPARATUS FOR PRODUCING COMPOUND METAL OBJECTS.

Application filed January 7,

To all whom it may concern:

Be it known that I, BYRON E. ELnR-ED, a citizen of the United States, residing at Bronxville, in the county of Vvestchester and State of New York, have invented a certain new and useful Method of-and Apparatus for Producing Compound Metal Objects; and I do hereby declare the following to be a full, clear, and exact description of the same, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to a method of and apparatus for producing bodies of metals of extremely high melting point, (platinum, iridium, etc.,) weld-united to bodies of ferrous .metals of lower melting point, iron or steel. for example, and consists in the novel steps of the process and in the novel apparatus employed for carrying out the process.

Notwithstanding its high cost, platinum is extensively used .for many purposes to which it is especially fitted by reason of its extremely high melting point, its substantial freedom from attack by acids, alkalis, oxygen, and many other chemical substances, its particular rate of expansion or contraction with changes of temperature, its electrical conductivity, its power of collecting and parting with a surface layer of oxygen, hydrogen and other gases catalytic power, its color and surface appearance, and other well-known qualities.

Its well-known softness, ductility, weakness under tensile and other "stresses, and inability to take a temper militate against or prevent its use for many purposes, however; and while it is commonly used in the form of sheets, wires, crucibles and other vessels, all of extreme thinness, nevertheless it is usually the surface qualities only of the metal which dictate its use; and a platinum coating on another or stronger metal, the coating being of almost infinitesimal thickness as compared with the platinum sheets, wires, -etc., ordinarily used, and entirely too thin to support itself in pieces of material size except for the support received from the other metal, is for many purposes quite as good as, and even better than, solid platinum, provided the platinum terial at first passing the platinum and servcoating and backing of other metal are firmly and inseparably united. It has been found extremely difiicult to unite platinum Specification of Letters Patent.

and vapors, its

molten ing to the method set to iron, and similar metals of. moderately high melting point, heretofore, although to some metals of lower melting point it unites more readily. By the method herein described, however, iron or steel, and various other similar metals of about the same meltlng point may be united to platinum quite easily, the union produced being, actually or substantially, a weld-union, the joined metals being inseparable by the action of heat or cold, or by a stripping action as by means of a cold chi el attempting to follow the line of union.

My invention, stated in its simplest terms, consists in casting against a clean surface of a piece of'platinum, a body of iron, steel, or metal of high melting point which has been heated to a very high temperature approximating the melting temperature of the platinum, and permitting the metal so cast to solidify against such platinum surface. I perform the casting under conditions affording a clean surface of the platinum and a clean. body of molten metal,

and which obviates the existence of an intermediate film of air or other gas.

According to my invention, as I commonly carry it out, a body of platinum of the desired size and shape is placed within a suitable mold constructed so as to permit a considerable quantity of molten material to be flowed against and along the surface of such' platinum body before the portion of molten metal which is to be united to the, platinum reaches it; the platinum being thereby highly heated and at the same time any adhering film of air, oxygen, or. other gas being wiped off. And commonly the metal so cast is east through a deep layer of molten borax or other flux, accordfortli in the applications of J. F. Monnot, Sr. Nos. 391,673, and 391,674, to insure good quality of the cast metal, its freedom from oxid and entrained or, occluded gases, etc. The mold used is of U-form and filled with flux, the platinumbody being-placed in one side of this mold, which is of such size and shape as to permit the molten metal to be poured down through that side of the mold and up into the other side thereof displacing the flux in a molten condition, the molten maing to highly heat the same and to remove any surface layer of air or other gas or sub- Patented Nov. 5, 1912. f 1908, Serial No. 409,617. Renewed May 9, 1913. Serial No. 696,276.

stance; the portion of the molten metal which finally solidifies in proximity to the platinum surface being a portion which has reached such vicinity only after the plat1- num and the mold have been heated to substantially the temperature of such molten metal. Preferably, the mold is completely filled-with molten borax or other suitable flux to form a deep layer therein before the molten metal is so poured into it, such molten metal being poured into the mold through the flux layer, and having all oxid, entrained and occluded gases removed thereby; the flux layer being finally displaced by the molten metal. For heating the molten metal to the desired temperature, any suitable means may be employed capable of producing the temperatures required, about 2900 R, such for example as an electric furnace. l have found the well-known heating substance called thermit very suitable as a source ofhigh-temperature iron or steel.

The accompanying drawings illustrate apparatus suitable for carrying out the process as above described.

In said drawings: Figure 1 shows more or less diagrammatically a vertical-transverse section of a mold such as may be used in carrying out said process, with a tube of platinum or like metal therein; Fig. 2 illustrates one method of heating the metal to be cast, and shows a central vertical section of a crucible containing thermit mixture.

In said drawings, 1 designates a mold cavity of general U-shape, formed in a block 2 of suitable refractory material and 3 designates a tube to form the coating of the finished ingot or billet, said tube being of platinum or other metal of extremely high melting point.

4 designates a body of molten flux or wiping material within the mold and which will be displaced by the molten metal when the latter flows into the mold. In

-Fig. 2, 5 designates such a body of thermit mixture (iron oxid and powdered aluminum) within a crucible 6, 7 designates aprimer of powdered magnesium and 8 a fuse by which the magnesium powder may be ignited; a strip of celluloid makes a satisfactory fuse.

In carrying out the process the tube 3 is placed within the mold and preferably the mold is then filled with a molten body 'of flux or wiping material, the crucible 6 is charged with thermit mixture and the primer and fuse added and the fuse ignited, said fuse in turn igniting the primer of powdered magnesium, which in turn ignites the thermit mixture. The product of reaction of the ingredients of the thermit mixture is alumina and molten iron, the alum'ina forming a slag which floats on the, surface of the molten iron. The proportions and quantities of thermit ingredients are so regulated in the charge as to produce the desired quantity of molten iron and the desired temperature of such iron. If it is desired that the ferrous metal to be united to the platinum or like metal, shall be steel, a suitable quantity of ferro-manganese or other vehicle for imparting carbon and other desired ingredients to the steel, is then introduced, after removing the slag, into the molten iron. The molten iron or steel is then poured into the mold. As it passes into the mold it passes through the body of molten flux therein which it also displaces and is wiped'free thereby of occluded and entrained gases, oxid impurities,'etc. The first quantity of molten metal so poured is passed through the side of the U- shaped mold orifice 1 containing the tube 3 into the other side thereof, in so doing heating the mold and the tube 3 to nearly or quite the temperature of the molten metal. The molten flux displaced by the molten metal flows out through gutters 9 and 10. If desired some of the molten metal itself may be permitted to escape from the mold through 10 although this will not ordinarily be desirable or necessary. The molten metal which finally fills that portion of the mold within which the tube 3 is, will reach that tube when the latter is at practicallythe temperature of the molten metal, and this temperature,

being near the melting point of the metal of said tube 3, said tube and the molten metal unite by a union corresponding to and equivalent to a weld union, and. when the molten metal solidifies both the tube, or coating, as it now is, and the core or cast metal, are inseparably united. The excess of cast metal beyond the end or ends ofthe coating is then cut off, and the coated billet so produced is worked to condense the cast metal and to reduce said billet to commercial form. In such working, the comparatively thin layer of platinum between the comparatively stifi' metal of the core and the working tool is much compacted and hardened.

The molten material flowing into the tube 3. not only serves to heat said tube but also to wipe therefrom any traces of gas adhering to or in proximity to its surface. This function becomes especially important when the coa ing metal is platinum; for it is well known that platinum has to a high degree the po of collecting adsorbed oxygen, hydrogen and other gases and vapors, which at the intense temperature of the molten metal not only tend to combine with such molten metal and so injure the a same, but also to form bubbles 'or blow holes between the coating and the cast core, both of .which conditions tend to prevent the formation of the desired union. But the tube fitting closely to the sides drawing down a molten material washing along the surface of the tube 3, will remove all such adsorbed gaseous layers as well as any trace of surface impurity. The wiping liquid is useful to insure a sound core casting and it also helps materially to secure the desired union between the core and coating tube.

While in the drawing the particular latinum article to be united to the metal of ower melting 'point is shown as being a of the mold, the molten metal being cast into its interior, it is obvious that the particular shape shown is not material to the invention. The tube form is suitable for the production of an ingot from which platinum-coated wire and the like may be drawn. It is obvious that by employing proper molds, and proper forms of platinum objects to be united to a base metal body, ingots, slabs, or blanks of non-platinum metals coated with platimum on the outside,

or inside, or both or all sides, may be produced. Likewise the same method may be employed in producing objects coated with iridium or other met-a1 of extremely high melting point.

Platinum-coated iron wire, produced by platinum-iron billet produced as above described, is particularly suited for use as leading-in wire for incandescent electric lamps and other exhausted glass articles and the like, iron, like platinum, having a rate of expansion and contraction approaching that of many kinds of glass, and having a sufiiciently high melting point to enable it to withstand the heat of molten or softened glass. But the use of iron leading-in wires has not been practicable heretofore, because of the impossibility of producing a gas-tight joint be: tween iron and glass; such difficulty not being experienced, however, in the case of platinum. So far as forming a oint between it and glass is concerned,'the platinum-covered iron wire behaves in the same way as solid platinum, the platinum sheath forming, so to speak, a linking means, cohering firmly on the one side to the iron and on the other to the glass. Iron wire coated with platinum as described is also suitable for use as resistance wire, the platinum covering preventing oxidation of the iron beneath, even when the latter is heated to a high temperature. For many purposes the platinum-covered iron has important advantages as compared with solid platinum, being much stronger and harder, and, in the case of steel-covered platinum the steel of which contains a proper proportion of carbon, being capable of being hardened and tempered the same as steel. For leading-in wires rous metal used may advantageously be nickel or cobalt steel. By varying the proportion of nickel in nickel steel, the coprising a particularly, the fer eflicient of expansion of the steel may be varied within considerable limits so as to make the coefli'cient of the compound metal wire as a whole exactly or substantially equal to that of the particular glass in which the leading-in wire is to be sealed.

t For-many purposes for which platinum is now used, it is desirable to have a certain amount of superficial porosity; as where its catalytic powers are utilized, such porosity increasing the total absorbing surface, and in use for such purposes, it is frequently found that its porosity increases. The superficial porosity of the platinum may be even purposely increased by suitable treatments where the compound metal is to be used for catalytic purposes, as in the oxidation of sulfur dioxid, in the manufacture of aldehydes, in self-lighting gas burners, etc. Forsuch purposes, the compound metal after manufacture may be partially superficially corroded, as by exposure to mixtures of reacting gases, or it may-be wetted with a solution of a platinum salt and heated.

By the term metal of extremely high melting point, used herein, I mean a metal the melting temperature of which is in excess of 2900 F., or in excess of the melting point of iro What I claim is 1. The process of producin compound bodies of unlike metals wel ed together comprising a metal of a melting point above 2900 F. and a ferrous metal having a melting point below 2900 F., which consists in contacting with a body of such metal of of the other said metal heated to a. temperature approximating the melting point of such high melting point metal, and permitting the molten metal to solidify against the surface of such high melting metal.

2. The process of producing compound bodies of unlike metals welded together commetal of the platinum group and a ferrous metal, which consists in contacting with a body of such metal of the platinum group a molten body of the other said metal heated to a temperature approximating the melting point of such platinum group metal, and permitting the molten metal to solidify against the surface of such platinum group metal.

i 3. The process of producing compound bodies of. unlike metals welded together, comprising atinum and a ferrous metal, which consists ontacting with a body of such platinum a molten body of the other said metal heated to a temperature approximating the melting point of such platinum, and permitting-the molten metal to against the surface of' the platinum.

4. The process of producing compound bodies of unlike metals welded together, which consists in placing a body of one such solidify extremely high meltingpoint a molten body branch and against the surface metal within one branch of a .U-shaped mold cavity, pouringmolten metal through such of the object therein, into the other branch of the mold, and permitting the metal so cast to solidify. i

5. The process of producing compound bodies of unlike metals welded together, which consists in pouring into one branch of a U-shapd mold cavity containing a body of molten wiping material and a body of one of the metals to be united, a molten mass of other metal, pouring said molten metal through such wiping material and said branch until the other branch fills, and pervmitting the metal, so cast to solidify.

6. The process of producing compound bodies of unlike metals welded together which consists in placing within one branch of a U-shaped mold a body of metal of ex- 'tremely high melting point and pouring into such branch of such mold and past the I surface of such object until the other branch fills, a body of unlike metal of lower melting point heated to approximately the melting point of such high melting metal and permitting the molten metal so cast to solidify.

7 Apparatus. for producing" compound bodies .of unlike metals welded together comprising a mold having a U-shapcd mold cavity, one branch of said cavity being adapted to receive a solid metal object and having a cupped mouth adapted to receive molten metal cast thereinto and the other branch of said cavity being adapted to re ceive an excess of metal passing through said first branch.

8. The process of producing compound -bodiesof unlike metals welded together which consists in producing a highly heated body of molten inetal the exothermic reaction of iron oxid and an oxidizable substance, casting the highly heated molten iron so produced against the surface of a body of platinum group metal to which iron is to be united, and permitting the molten metal so cast to solidify.

9. The process of producin compound bodies of unlike metals wel ed together which consists in producing a body of hi hly heated molten ferrous metal by the exot ermic reaction of aluminum and iron oxid, casting the highly heated molten ferrous metal so produced against the surface of a body of platinum group metal to which iron,

is to be united, and permitting the molten metalso cast to solidify.

10. The process of producing platinum clad metal which com-p)r1ses producing highly heated molten metal y the reaction of-aluminum on a metal oxid, and casting such metal priorto losing a substantial amount of the heat of reaction into contact with solid platinum, said casting being through a body of flux.

11. The process of producing platinum clad steel. which comprises producing highly heated molten ferrous metal by the reaction of aluminum on oxid comprising iron oxid, and casting such metal prior to losing a substantial amount of the heat of reaction into contact with solid platinum, said casting being throu h a body of flux.

In testimony whereof afiix my signature, in the presence of two witnesses.

BYRON E. ELDRED.

Witnesses:

PHILLIPS BLAGDEN, H. M. MARBLE. 

